The present invention relates to fluoropolymer compositions for imparting oil- and water-repellency to textiles by solvent application.
The patent literature discloses numerous fluoropolymer compositions having utility as textile treating agents. These fluoropolymers generally contain pendent perfluoroalkyl groups of three or more carbon atoms, which provide oil- and water-repellency when the compositions are applied to fabric surfaces. Methods for producing such polymers, either in aqueous emulsion or in solvent systems, are well known.
Generally, oil- and water-repellent fluoropolymers are applied to textiles as a latex emulsion in an aqueous bath. However, there are a number of applications wherein application of fluorochemical textile finishes from organic solvent media is desirable. For example, solvent-applied finishes can be used on particular fabrics, e.g., expensive upholstery, where unique or delicate fabric characteristics preclude use of water-based materials. Solvent finishes are also ideally suited for use by commercial dry-cleaners, who employ conventional dry cleaning equipment and solvents for both cleaning and refurbishing of rainwear. In addition, solvent finishes can be applied to textiles from aerosols, which are convenient for the home consumer.
The customary means of preparing a textile finish for solvent application is to dissolve the active ingredient in a suitable organic solvent. In the case of many fluorochemical textile finishes, however, this presents a problem because these compounds generally have inherent insolvency in most non-polar solvents. Moreover, difficulties are encountered in achieving uniform application, or spreading, of the fluoropolymer on the textile surface prior to evaporation of solvent. Too-rapid solvent evaporation results in "frosting", particularly on dark fabrics.
Finally, many organic solvents are toxic or highly flammable, necessitating stringent environmental controls. New non-hazardous, non-flammable solvent-borne fabric treatment agents with superior performance are of significant interest to the apparel, furnishings, and textile industries, as well as to home users of aerosol fabric treatment agents.